Objective: To explore the prognostic significance of p53 and ATM gene deletion in patients with chronic lymphocytic leukemia (CLL).
Methods: Interphase fluorescence in situ hybridization (FISH) and probes of LSI p53 and LSI ATM were used to detect p53 and ATM gene deletion in 80 patients with CLL. p53 and ATM gene deletion and their association with some prognostic factors were analyzed. The Kaplan-Meier method was used to calculate survivals, and results were compared using the Log-rank test. Multivariate COX regression analysis was used to assess associations between survival and potential risk factors.
Results: Out of the 80 CLL patients, p53 gene deletion was found in 14 (17.5%) cases, ATM gene deletion in 9 (11.3% ) cases, and both the two genes deletion in 3 (3.8%) cases. There was no significant differences of p53 and ATM gene deletion rates in sex, age, Binet stages, peripheral lymphocyte count, and the levels of LDH, beta2-MG, and ZAP-70. The p53 and ATM gene deletion rates were higher in the group of CD38 high expression than that in the group of low expression (P=0.025 and P=0.001). Among 41 patients who received fludarabine containing protocol, none of the nine cases with p53 and/or ATM gene deletion achieved complete response (CR), while 12 of 32 (37.5%) cases without the gene deletion achieved CR. The survival time was shorter in patients with p53 gene deletion (P<0.01). There was no association between outcome and ATM gene deletion (P=0.556). On multivariate analysis by COX regression, p53 gene deletion and CD38 expression (P=0.014 and P=0.017, respectively) were found to be independent factors in predicting survival.
Conclusion: CLL patients with p53 and/or ATM gene deletion had poor therapeutic effect, and hence poor prognosis.